Lubricants with improved seal compatibility

ABSTRACT

The present invention relates to industrial gear lubricating compositions that include a specific class of substituted triazoles, where the substituted triazole includes at least one hydrocarbyl group linked to one of the nitrogen atoms in the triazole ring. Such compositions provide surprisingly good seal compatibility compared to compositions with other triazoles and/or alternative additives.

FIELD OF THE INVENTION

The present invention relates to lubricating compositions andparticularly gear oil compositions that include a specific class ofsubstituted triazoles, where the substituted triazole includes at leastone hydrocarbyl group linked to one of the nitrogen atoms in thetriazole ring. Such compositions provide surprisingly good sealcompatibility compared to compositions with other triazoles and/oralternative additives.

BACKGROUND OF THE INVENTION

In many industrial applications lubricating compositions come intocontact with seals within the equipment in which they are used. Sealsare made out of various materials, including nitrile-butadiene rubber(NBR) due to its relatively low cost and high availability, as well asfluorinated elastomers, silicones, and polycarbonates. It is essentialthat the lubricating composition used has good compatibility with theseals otherwise seals are degraded over time to the point that theyfail, leading to fluid leakage increasing maintenance costs, longer downtime for the equipment, and even the risk of equipment damage.

Seals, particularly those made using NBR, break down over time undereven normal operating conditions. High temperatures in particular can bevery detrimental to some seals. In other cases seals can sometimes besusceptible to attack by chemical additive components of somelubricating compositions, including those used frequently in industrialapplications, including some extreme-pressure agents like sulfurizedolefins, rust inhibitors like aminic compounds, antiwear agents likephosphates, phosphites, phosphate esters, and phosphate amine salts. Insome cases even the base oil itself can attack seal materials includingNBR.

There is an on-going need for industrial lubricating compositions thatcan provide the required performance and protection for the equipment,but which also protect the seals attack or degradation thus reducing therisk of lubricant leakage, down time and ultimately equipment damage orfailure.

Wind turbines in particular represent an industrial application thatrequires lubricating compositions with good seal compatibility. Windturbines as an alternative renewable energy source are attracting moreinterest, since they produce electricity by converting clean wind energyto electrical energy. A gear box, which is typically situated betweenthe rotor of the wind turbine and the generator, requires a lubricant.The high torque puts a large amount of stress on the gears and bearingsin the gear box of these wind turbines, placing high performancerequirements on the lubricating composition. In addition, the gear boxesare located in nacelles of the wind turbine high off the ground and theunit themselves are often in remote areas. Thus the gear boxes are ofteninaccessible or only accessible with great cost and difficulty such thata long service life with limited maintenance is desired. Lubricatingcompositions with improved seal compatibility but which still providegood lubricating performance are expected to reduce maintenance and downtime caused by failed seals. Thus there is a need for lubricatingcompositions with improved seal compatibility, that still provide goodlubricating performance in wind turbines and similar applications.

SUMMARY OF THE INVENTION

The invention provides a lubricating composition comprising (i) an oilof lubricating viscosity and (ii) a substituted triazole where thesubstituted triazole includes at least one hydrocarbyl group linked toone of the nitrogen atoms in the triazole ring. In some embodiments thelubricating composition is an industrial lubricating composition, thatis a lubricating composition for an industrial application, includingfor example, wind turbines. Thus in some embodiments the inventionprovides a wind turbine lubricating composition.

In some embodiments the substituted triazole is present in thelubricating composition from 0.05 to 1.0 percent by weight.

The invention provides for substituted triazoles having the formula:

or a combination thereof; where, for both formula I and formula II: n isan integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or—(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group, —R²— is ahydrocarbylene group, m is 0 or 1, and each —R³ is independentlyhydrogen or a hydrocarbyl group, so long as the —R¹, —R²—, and each —R³overall, including whichever are present, contain from 6, 7, 8 or even 9up to 40 carbon atoms combined (in other words the ranges here refer tothe total number of carbon atoms in the Y group). In some embodiments,when Y is —R¹, R¹ may contain from 6 or 8 up to 40 carbon atoms, andwhen Y is —(R²)_(m)—NR³R³, the —R¹, —R²—, and each —R³ groups overallmay contain from 7 or even 9 to 40 carbon atoms combined.

The invention provides for the described compositions where the oil oflubricating viscosity includes a mineral base oil, where the oil oflubricating viscosity includes a synthetic base oil, and even where theoil of lubricating viscosity includes a combination of a mineral baseoil and a synthetic base oil. In some embodiments the oil of lubricatingviscosity is substantially free of, or even free of, a synthetic esterbase oil.

The invention also provides for the compositions containing asubstituted triazole where the substituted triazole is the reactionproduct of a triazole, an aldehyde and an amine.

The invention provides a method of lubricating a gear assemblycomprising supplying to said assembly a lubricating compositioncomprising (i) an oil of lubricating viscosity and (ii) a substitutedtriazole where the triazole includes at least one hydrocarbyl grouplinked to one of the nitrogen atoms in the triazole ring. Any of thesubstituted triazoles described herein may be used in such methods.

The invention provides for the use of the described substitutedtriazoles in lubricating compositions as a seal protectant, includinglubricating compositions for industrial applications. The inventionprovides even more specifically for wind turbines and other applicationsthat require fatigue or micro-pitting resistant formulations and evenapplications that have stringent seal compatibility requirements.

DETAILED DESCRIPTION OF THE INVENTION

Various features and embodiments of the invention will be describedbelow by way of non-limiting illustration.

The invention provides a lubricating composition comprising (i) an oilof lubricating viscosity and (ii) a substituted triazole where thesubstituted triazole includes at least one hydrocarbyl group linked toone of the nitrogen atoms in the triazole ring, as well as methods ofusing such compositions. The compositions of the present invention mayalso include one or more additional additives.

The Oil of Lubricating Viscosity

One component of the compositions of the invention is an oil oflubricating viscosity, which can be present in a major amount, for alubricant composition, or in a concentrate forming amount, for aconcentrate.

Suitable oils include natural and synthetic lubricating oils andmixtures thereof. In a fully formulated lubricant, the oil oflubricating viscosity is generally present in a major amount (i.e. anamount greater than 50 percent by weight). Typically, the oil oflubricating viscosity is present in an amount of 75 to 95 percent byweight, and often greater than 80 percent by weight of the overallcomposition. The base oil component generally makes up 100 parts byweight (pbw) of the overall composition with the pbw ranges for theother components being provided with this 100 pbw of base oil in mind.In other embodiments the pbw ranges of the various components, includingthe base oils, are provided such that the total of the pbw of allcomponents is 100, and thus the pbw values are equivalent to percent byweight values. The pbw ranges provided for the various componentsdescribed below may be taken either way, however in most embodimentsthey are to be read so as to be equivalent to percent by weight values.

The oil of lubricating viscosity may include natural and synthetic oils,oil derived from hydrocracking, hydrogenation, and hydrofinishing,unrefined, refined and refined oils or mixtures thereof. Unrefined oilsare those obtained directly from a natural or synthetic source generallywithout (or with little) further purification treatment. Refined oilsare similar to the unrefined oils except they have been further treatedin one or more purification steps to improve one or more properties.Purification techniques are known in the art and include solventextraction, secondary distillation, acid or base extraction, filtration,percolation and the like. Re-refined oils are also known as reclaimed orreprocessed oils, and are obtained by processes similar to those used toobtain refined oils and often are additionally processed by techniquesdirected to removal of spent additives and oil breakdown products.

Natural oils useful as the oil of lubricating viscosity include animaloils, vegetable oils (e.g., castor oil, lard oil), mineral lubricatingoils such as liquid petroleum oils and solvent-treated or acid-treatedmineral lubricating oils of the paraffinic, naphthenic or mixedparaffinic naphthenic types and oils derived from coal or shale ormixtures thereof.

Synthetic oils of lubricating viscosity include hydrocarbon oils such aspolymerized and interpolymerised olefins (e.g., polybutylenes,polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes),poly(1-octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls, terphenyls,alkylated polyphenyls); alkylated biphenyl ethers and alkylated biphenylsulfides and the derivatives, analogs and homologs thereof or mixturesthereof.

Another synthetic oil of lubricating viscosity includes polyol estersother than the hydrocarbyl-capped polyoxyalkylene polyol as disclosedherein, dicarboxylic esters, liquid esters of phosphorus-containingacids (e.g., tricresyl phosphate, trioctyl phosphate, and the diethylester of decane phosphonic acid), or polymeric tetrahydrofurans.Synthetic conventional oil of lubricating viscosity also include thoseproduced by Fischer-Tropsch reactions and typically may behydroisomerised Fischer-Tropsch hydrocarbons or waxes. In oneembodiment, the oil of lubricating viscosity may be prepared by aFischer-Tropsch gas-to-liquid synthetic procedure as well as othergas-to-liquid oils.

Oils of lubricating viscosity may further be defined as specified in theAmerican Petroleum Institute (API) Base Oil InterchangeabilityGuidelines. The five base oil groups are as follows: Group I (sulfurcontent >0.03 wt %, and/or <90 wt % saturates, viscosity index 80-120);Group II (sulfur content ≦0.03 wt % and ≧90 wt % saturates, viscosityindex 80-120); Group III (sulfur content ≦0.03 wt % and ≧90 wt %saturates, viscosity index ≧120); Group IV (all polyalphaolefins PAOssuch as PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8); and Group V. Theoil of lubricating viscosity includes API Group I, Group II, Group III,Group IV, Group V oil or mixtures thereof. In one embodiment, the oil oflubricating viscosity is an API Group I, Group II, Group III, Group IVoil or mixtures thereof. Alternatively, the oil of lubricating viscosityis often an API Group II, Group III or Group IV oil or mixtures thereof.

The various described oils of lubricating viscosity may be used alone orin combinations. The oil of lubricating viscosity is used in the rangeof about 70 wt % to about 99 wt %, and in another embodiment, in therange of about 75 wt % to about 98 wt %, in another embodiment in therange of about 88 wt % to about 97 wt % of the lubricant.

In some embodiments the lubricating oil component of the presentinvention includes a Group II or Group III base oil, or a combinationthereof. These are classifications established by the API (AmericanPetroleum Institute). Group III oils contain <0.03 percent sulfurand >90 percent saturates and have a viscosity index of >120. Group IIoils have a viscosity index of 80 to 120 and contain <0.03 percentsulfur and >90 percent saturates. The oil can also be derived from thehydroisomerization of wax, such as slack wax or a Fischer-Tropschsynthesized wax. Such “Gas-to-Liquid” oils are typically characterizedas Group III.

The compositions of the present invention may include some amount ofGroup I base oils, and even Group IV and Group V base oils.Polyalphaolefins are categorized as Group IV. Group V encompasses “allothers”. However, in some embodiments the lubricating oil component ofthe invention contains no more than 20, 10, 5, or even 1 percent byweight Group I base oil. These limits may also apply to Group IV orGroup V base oils. In other embodiments the lubricating oil present inthe compositions of the invention is at least 60, 70, 80, 90, or even 95percent by weight Group II and/or Group III base oil. In someembodiments the lubricating oil present in the compositions of theinvention is essentially only Group II and/or Group III base oil, wheresmall amounts of other types of base oils may be present but not inamounts that significantly impact the properties or performance of theoverall composition.

In some embodiments the compositions of the invention include someamount of Group I and/or Group II base oils. In other embodiments thecompositions of the invention are lubricating compositions where the oilof lubricating viscosity is primarily Group I and/or Group II base oils,or even essentially Group I and/or Group II base oils, or evenexclusively Group I and/or

Group II base oils.

In some embodiments the compositions of the invention include someamount of Group I base oils. In other embodiments the compositions ofthe invention are lubricating compositions where the oil of lubricatingviscosity is primarily Group I base oils, or even essentially Group Ibase oils, or even exclusively Group I base oils.

In some embodiments the compositions of the invention include someamount of Group II base oils. In other embodiments the compositions ofthe invention are lubricating compositions where the oil of lubricatingviscosity is primarily Group II base oils, or even essentially Group IIbase oils, or even exclusively Group II base oils.

In some embodiment's the oil of lubricating viscosity may be present inthe range from 60 to 99.9, from 88.5 to 99.6, from 96.9 to 99.5, or from98.2 to 99.4 weight percent of the lubricating oil composition. Each oilof lubricating viscosity described above may be used alone or asmixtures of one or more thereof.

The Substituted Triazole

The lubricating compositions on the invention include a substitutedtriazole where the substituted triazole includes at least onehydrocarbyl group linked to one of the nitrogen atoms in the triazolering. The substituted triazole includes substituted benzotriazoles, andin some embodiments the substituted triazole is a substitutedbenzotriazole. In some of these embodiments the hydrocarbyl group linkedto one of the nitrogen atoms in the triazole ring does not contain anyoxygen atoms.

In some embodiments the substituted triazole has a single hydrocarbylgroup linked to a nitrogen atom on the triazole ring. In someembodiments the substituted triazole contains an aryl group linked and asingle hydrocarbyl group linked to a nitrogen atom on the triazole ring.

The hydrocarbyl group of the substituted triazole is considered to be animportant feature of the invention. The hydrocarbyl group may be linearor branched, however in some embodiment the hydrocarbyl group isbranched. In some embodiments the hydrocarbyl contains at least onenitrogen atom, and in further embodiments the hydrocarbyl contains asingle nitrogen atom. In these embodiments, where a nitrogen atom ispresent, the substituent group is still referred to herein as ahydrocarbyl group. In still further embodiments the hydrocarbyl group:contains a single nitrogen atom, is branched at one or more points, andthe nitrogen atom is itself a branch point. In other words, in someembodiments the hydrocarbyl group of the substituted triazole can bedescribed as —R¹—NR²R² where each R¹ is a hydrocarbyl group, and morespecifically a hydrocarbylene group, and each R² is a hydrocarbyl groupthat contains at least one carbon atoms. In such embodiments the R¹ andR² groups may themselves be linear or branched hydrocarbyl groups. Insome embodiments R¹ is a linear hydrocarbyl group while both R² groupsare identical branched hydrocarbyl groups.

In any of these described embodiments the hydrocarbyl group linked toone of the nitrogen atoms in the triazole ring may contain from 6 to 40carbon atoms, or may contain from about 6, 8, 10, 12, 14, or 16 carbonatoms up to 40, 30, 20, or 18 carbon atoms. In some embodiments thehydrocarbyl group contains 16 to 18 carbon atoms and one nitrogen atom.

In some embodiments the hydrocarbyl group linked to one of the nitrogenatoms in the triazole ring is a nitrogen-containing group where thenitrogen atom in the hydrocarbyl group is connected to the nitrogen inthe triazole ring by one or two carbon atoms and wherein the nitrogenatom itself, in addition to the connected to the triazole ring, alsocontains two hydrocarbyl groups which are identical branched alkylgroups containing and in some embodiments contain 6 to 10 carbon atomseach. Examples of suitable branched alkyl groups include 2-methylpentyl,2-methylhexyl, 3-methylheptyl, 4-methyloctyl, 2-ethylpentyl,2-ethylhexyl, 3-ethylheptyl, 4-ethyloctyl, 2-propylheptyl, etc.

In some embodiments the substituted triazole may be represented by thefollowing formulas:

or a combination thereof; where, for both formula I and formula II: n isan integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or—(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group, —R²— is ahydrocarbylene group, m is 0 or 1 or 2, and each —R³ is independentlyhydrogen or a hydrocarbyl group, so long as the —R¹, —R²—, and —R³overall contain from 7 or even 9 to 40 carbon atoms combined. In someembodiments the substituted triazole of the invention is represented byFormula (I).

In some embodiments: n may be from 0 or 1 up to 4, 3, 2 or 1; R may be ahydrocarbyl group and may contain from 1 to 50 carbon atoms, or from 1or 2 up to 40, 30, 20, 18 or even 8 carbon atoms, and in someembodiments contains 1 or 2 carbon atoms; within Y, m may be 0 or 1 or 2and in some embodiments 1 or 2; R¹ may be a hydrocarbyl group and maycontain from 1, 6, 10 or 12 up to 40, 30, 20, or even 18 carbon atoms;R² may be a hydrocarbylene group and may contain from 1, 6, 10 or 12 upto 40, 30, 20, 18, or even 8 carbon atoms or even 1 to 8 carbon atomsand in some embodiments contains 1 carbon atom; R³ may be hydrogen or ahydrocarbyl group and may contain from 1, 6, 10 or 12 up to 40, 30, 20,18, or even 8 carbon atoms or even 1 to 8 carbon atoms and in someembodiments contains 8 carbon atoms, so long as Y contains from 8 to 40carbon atoms.

In some embodiments —Y is —R¹, —R²—NHH, —R²—NHR³, —R²—NR³R³ where thevarious R groups can have any of definitions provided above again solong as the Y group contains overall 6 or 7 or even 9 up to 40 carbonatoms.

In some embodiments all of the hydrocarbyl groups described above arefree of oxygen atoms. In some embodiments all of the hydrocarbyl groupsdescribed above are free of all heteroatoms and are purely alkyl groupsexcept for a single nitrogen atom present in the Y group.

The substituted triazole of the invention may be prepared by condensinga basic triazole via its acidic —NH group with an aldehyde and an amine.In some embodiments the substituted triazole is the reaction product ofa triazole, an aldehyde and an amine. Suitable triazoles that may beused to prepare the substituted triazole of the invention includebenzotriazole, while suitable aldehydes include formaldehyde andreactive equivalents like formalin, while suitable amines includeprimary or secondary amines. In some embodiments the amines aresecondary amines and further are branched amines. In still furtherembodiments the amines are beta-branched amines, for examplesbis-2-ethylhexyl amine.

The compositions of the invention typically include the substitutedtriazole from 0.05 to 1.0 percent by weight, but may also include from0.05 or 0.1 up to 1.0 or 0.5 percent by weight of the substitutedtriazole. In some embodiments the composition of the invention containsno more than 1, 0.75, or even 0.5 percent by weight substitutedtriazole. In some embodiments the composition of the invention containsat least 0.05, 0.07, or even 0.1 percent by weight substituted triazole.

Additional Additives

Optionally the lubricating compositions of the invention include one ormore additional additives, which may be selected from the groupincluding: a foam inhibitor, a demulsifier, a pour point depressant, anantioxidant other than those described above, a dispersant, a metaldeactivator (such as a copper deactivator), an antiwear agent, extremepressure agent, viscosity modifiers, or mixtures thereof, The optionaladditives may each be present in the range from 0.0005 to 1.3, from0.00075 to 0.5, from 0.001 to 0.4, or from 0.0015 to 0.3 percent byweight of the lubricating oil composition. However it is noted that someoptional additives, including viscosity modifying polymers, which mayalternatively be considered as part of the base fluid, may be present inhigher amounts including up to 30, 40, or even 50% by weight whenconsidered separate from the base fluid. The optional additives may beused alone or mixtures thereof.

Antifoams, also known as foam inhibitors, are known in the art andinclude but are not limited to organic silicones and non-silicon foaminhibitors. Examples of organic silicones include dimethyl silicone andpolysiloxanes.

Examples of non-silicon foam inhibitors include but are not limited topolyethers, polyacrylates and mixtures thereof as well as copolymers ofethyl acrylate, 2-ethylhexylacrylate, and optionally vinyl acetate. Insome embodiments the antifoam is a polyacrylate. Antifoams may bepresent in the composition from 0.001 to 0.012 or 0.004 pbw or even0.001 to 0.003.

Demulsifiers are known in the art and include but are not limited toderivatives of propylene oxide, ethylene oxide, polyoxyalkylenealcohols, alkyl amines, amino alcohols, diamines or polyamines reactedsequentially with ethylene oxide or substituted ethylene oxides ormixtures thereof. Examples of demulsifiers include polyethylene glycols,polyethylene oxides, polypropylene oxides, (ethylene oxide-propyleneoxide) polymers and mixtures thereof. In some embodiments thedemulsifiers is a polyether. Demulsifiers may be present in thecomposition from 0.002 to 0.012 pbw.

Pour point depressants are known in the art and include but are notlimited to esters of maleic anhydride-styrene copolymers,polymethacrylates; polyacrylates; polyacrylamides; condensation productsof haloparaffin waxes and aromatic compounds; vinyl carboxylatepolymers; and terpolymers of dialkyl fumarates, vinyl esters of fattyacids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehydecondensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor.Suitable rust inhibitors include hydrocarbyl amine salts ofalkylphosphoric acid, hydrocarbyl amine salts of dialkyldithiophosphoricacid, hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid, fattycarboxylic acids or esters thereof, an ester of a nitrogen-containingcarboxylic acid, an ammonium sulfonate, an imidazoline, mono-thiophosphate salts or esters, or any combination thereof; or mixturesthereof.

Suitable hydrocarbyl amine salts of alkylphosphoric acid of theinvention are represented by the following formulas:

wherein R²¹ and R²² are independently hydrogen, alkyl chains orhydrocarbyl, and in some embodiments at least one of R²¹ and R²² arehydrocarbyl. R²¹ and R²² contain about 4 to about 30, about 8 to about25, or even about 8 or 10 to about 20, or even from 13 to about 19carbon atoms. R²³, R²⁴ and R²⁵ are independently hydrogen, alkylbranched or linear alkyl chains with about 1 to about 30, in otherembodiments about 4 to about 24, or even from about 6 to about 20, andin some embodiments about 8 or 10 to about 16 carbon atoms. R²³, R²⁴ andR²⁵ are independently hydrogen, alkyl branched or linear alkyl chains,and in some embodiments at least one, or even two of R²³, R²⁴ and R²⁵are hydrogen, and further where at least one of R²³, R²⁴ and R²⁵ is ahydrocarbyl group containing at least 8 carbon atoms.

Examples of alkyl groups suitable for R²³, R²⁴ and R²⁵ include but arenot limited to butyl, sec-butyl, isobutyl, tert-butyl, pentyl, n-hexyl,sec-hexyl, n-octyl, 2-ethyl, hexyl, ethyl-hexyl, decyl, undecyl,dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl,octadecyl, octadecenyl, nonadecyl, eicosyl or mixtures thereof.

In one embodiment the hydrocarbyl amine salt of an alkylphosphoric acidis the reaction product of a C₁₄ to C₁₈ alkylated phosphoric acid withPrimene 81R (produced and sold by Rohm & Haas) which is a mixture of C₁₁to C₁₄ tertiary alkyl primary amines.

Hydrocarbyl amine salts of dialkyldithiophosphoric acid of the inventionused in the rust inhibitor package are represented by the formula:

wherein R²⁶ and R²⁷ are independently branched or linear alkyl groups.R²⁶ and R²⁷ contain about 3 to about 30, preferably about 4 to about 25,more preferably about 5 to about 20, and most preferably about 6 toabout 19 carbon atoms. R²³, R²⁴ and R²⁵ are as described above.

Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid ofthe invention include but are not limited to the reaction product(s) ofdiheptyl or dioctyl or dinonyl dithiophosphoric acids withethylenediamine, morpholine or Primene 81R or mixtures thereof.

Suitable hydrocarbyl amine salts of hydrocarbyl arenesulphonic acidsused in the rust inhibitor package of the invention are represented bythe formula:

wherein Cy is a benzene or naphthalene ring. R²⁸ is a hydrocarbyl groupwith about 4 to about 30, preferably about 6 to about 25, morepreferably about 8 to about 20 carbon atoms. z is independently 1, 2, 3,or 4 and most preferably z is 1 or 2. R²³, R²⁴ and R²⁵ are as describedabove.

Examples of hydrocarbyl amine salts of hydrocarbyl arenesulphonic acidof the invention include but are not limited to the ethylenediamine saltof dinonylnaphthalene sulphonic acid.

Examples of suitable fatty carboxylic acids or esters thereof includeglycerol monooleate and oleic acid. An example of a suitable ester of anitrogen-containing carboxylic acid includes oleyl sarcosine.

The rust inhibitors may be present in the range from 0.02-0.2, from 0.03to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 pbw of the lubricatingoil composition. The rust inhibitors of the invention may be used aloneor in mixtures thereof.

The lubricating compositions of the invention may also include a metaldeactivator. Metal deactivators are used to neutralise the catalyticeffect of metal for promoting oxidation in lubricating oil. Suitablemetal deactivators include but are not limited to triazoles,tolyltriazoles, a thiadiazole, or combinations thereof, as well asderivatives thereof. Examples include derivatives of benzotriazolesother than those described above, benzimidazole,2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles,2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles,2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles,2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles,2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof. Theseadditives may be used from 0.01 to 0.25 percent by weight in the overallcomposition.

In some embodiments the metal deactivator is a hydrocarbyl substitutedbenzotriazole compound. The benzotriazole compounds with hydrocarbylsubstitutions include at least one of the following ring positions 1- or2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups containabout 1 to about 30, preferably about 1 to about 15, more preferablyabout 1 to about 7 carbon atoms, and most preferably the metaldeactivator is 5-methylbenzotriazole used alone or mixtures thereof.

The metal deactivators may be present in the range from 0.001 to 0.1,from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oilcomposition. Metal deactivators may also be present in the compositionfrom 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used aloneor mixtures thereof.

Antioxidants may also be present including (i) an alkylateddiphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide. In someembodiments the alkylated diphenylamines of the invention arebis-nonylated diphenylamine and bis-octylated diphenylamine. In someembodiments the substituted hydrocarbyl monosulfides includen-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, orcombinations thereof. In some embodiments the substituted hydrocarbylmonosulfide is 1-(tert-dodecylthio)-2-propanol.

The antioxidant package may also include sterically hindered phenols.Examples of suitable hydrocarbyl groups include but are not limited to2-ethylhexyl or n-butyl ester, dodecyl or mixtures thereof. Examples ofmethylene-bridged sterically hindered phenols include but are notlimited to 4,4′-methylene-bis(6-tert-butyl o-cresol),4,4′-methylene-bis(2-tert-amyl-o-cresol),2,2′-methylene-bis(4-methyl-6-tert-butylphenol),4,4′-methylene-bis(2,6-di-tertbutylphenol) or mixtures thereof.

In some embodiments the compositions of the invention are essentiallyfree of, or even completely free of alkylated phenols, alkaryl amines,or both, or contain them at not more than 2.0 percent by weight, 1.0percent by weight, or even 0.5 percent by weight where theses percentbuy weight values refer to the total amount of alkylated phenols and/oralkaryl amines present in the overall lubricant.

Dispersants may also be present including: (i) a polyetheramine; (ii) aborated succinimide dispersant; (iii) a non-borated succinimidedispersant; (iv) a Mannich reaction product of a dialkylamine, analdehyde and a hydrocarbyl substituted phenol; or any combinationthereof. In some embodiments the dispersant component is present from0.05 to 0.5 pbw of the overall composition.

The invention further provides for all of the compositions, methods, anduses described herein, where the specified lubricant includes ademulsifier, where the specified lubricant includes a combination of ademulsifier and a sulfurized olefin, where the specified lubricantincludes a highly sulfurized olefin such as a sulfurized olefincontaining at least 20% by weight sulfur, where the specified lubricantis essentially free or to even completely free of non-highly sulfurizedolefins such as a sulfurized olefin containing less than 20% by weightsulfur, where the specified lubricant includes a combination of asubstituted triazole and a substituted thiadiazole, where the specifiedlubricant is essentially free of or even completely free of metaldialkyl dithiophosphates, where the specified lubricant is essentiallyfree of or even completely free of overbased metal-containingdetergents, where the specified lubricant is essentially free of or evencompletely free of zinc, or any combination thereof.

INDUSTRIAL APPLICATION

The invention provides a process for the preparation of lubricating oilcompositions. The lubricating oil compositions are prepared by the stepscomprising: a) mixing and/or dissolving in one another the componentsdescribed above that includes the combination of an oil of lubricatingviscosity, the substituted triazole and optionally one more additionadditives. The materials are mixed until the additives are substantiallyor wholly dissolved, in some embodiments at elevated temperatures in therange 40° C. to 110° C., or 50° C. to 95° C., or even 55° C. to 85° C.;and for a period of time in the range 30 seconds to 24 hours, 2 minutesto 8 hours, or 5 minutes to 4 hours; and at pressures in the range 700mm of Hg to 2000 mm of Hg, 750 mm of Hg to 900 mm of Hg, or 755 mm of Hgto 800 mm of Hg.

The order of addition of the additives is not overly limited. Theoptional additives may be mixed in at the same time as the othercomponents or at a later time using any of the mixing proceduresdescribed above.

In some embodiments a portion of oil or similar diluent is present withthe components and the components are mixed into the oil. In otherembodiments a minimal amount of oil or diluent is present, other thanthat amount inherently present in the additive from their means ofproduction and preparation and additional base oil is added after thecomponent have been mixed. In any event the described processes resultsin lubricating compositions.

In some embodiments the lubricating oil compositions may be preparedfrom a concentrate comprising the steps of: a) mixing all of thecomponents described above with minimal oil and/or diluent present,other than optionally some relatively small amount to allow forreasonable handling properties. The resulting concentrate may then beused in the preparation of a lubricating composition by mixing theconcentrate with an effective amount of base oil or mixtures thereofresulting in a finished fluid. Optional additives may be added to theconcentrate or to the resulting final fluid. These optional additivesinclude any of those described above. In some embodiments these optionaladditives include a foam inhibitor, a demulsifier, a viscosity modifier,a pour point depressant, or mixtures thereof, and may be added such thatthey are present in the overall compositions in the range about 0, 0.01,0.1 or even 0.25 or up to about 13, 10, 8 or even 6 pbw.

In some embodiments the compositions of the invention have an ISOviscosity grade from 100 to 1000, or from 100 to 460, or even from 100or 150 to 320. In some embodiments the compositions of this inventionare not grease compositions or engine oil compositions. Rather thesecompositions can be industrial gear oils, wind turbine lubricants,bearing lubricants, and the like, and in some embodiments evenautomotive gear oils.

SPECIFIC EMBODIMENT

The invention will be further illustrated by the following examples,which set forth particularly advantageous embodiments. While theexamples are provided to illustrate the invention, they are not intendedto limit it.

The example sets below are designed to evaluate and compare thefollowing additives: Seal Additive A, an alkylated phenol; Seal AdditiveB, an alkaryl amine; Seal Additive C, a substituted benzotriazole whichmay be prepared by reacting tolytriazole with an aldehyde and2-ethylhexyl amine; and Seal Additive D, a substituted triazole whichmay be prepared by reacting triazole with an aldehyde and 2-ethylhexylamine. Seal Additives A and B do not meet the requirements for thesubstituted triazole of the invention.

To evaluate the additives, the examples in the example sets below aretested to evaluate their seal compatibility. Using SRE-NBR-28 seals thesamples are tested for approval under the DIN 51517-3 gear oilspecification (DIN), which involves 100 hours of testing at 100° C. foreach sample. Under this specification, the fluid must give a percenttensile decrease of no more than 30% (−30% max) and a percent elongationdecrease of no more than 40% (−40% max). Using NBR 902 seals the samplesare also tested for approval under the Flender-Siemens specification(F-S) for wind turbines, which involves 1000 hours of testing at 130° C.for each sample. Under this specification, ideally the fluid must giveresults including a hardness change of not more than 5 points (−5 to+5), a percent volume change from a 2% decrease to a 5% increase (−2% to+5%), a percent tensile decrease of no more than 60% (−60% max) and apercent elongation decrease of no more than 60% (−60% max). Thesespecifications, in particular the Flender-Siemens specification, arevery hard to meet, and a relative improvement in performance over aconventional comparative example, even if not a clean pass, would stillbe considered to be a significant improvement. In fact, a sample thatmeets the specification expect for having a hardness change up to +7, avolume change up to +6%, or a elongation change of down to −65% is stillconsidered to have met the a specification and passed the test, so longas only one of these areas is outside the normal pass range. Thissecondary allowance for one of the ratings allows for a passing resulteven if the sample did not show a “clean pass” with all ratings insidethe ideal ranges.

However, as is evident from the results, it is important to considerrelative performance of the examples rather than just the pass failresult. When considering the Flender-Siemens specification (F-S) resultsof the example sets and comparing the relative performance it can behelpful to consider the degree to which a sample passed or failed. Thefollowing key can be used for this purpose with the best result at thetop of the table and the worst result at the bottom:

Result Key for Relative Performance Comparisons Degree RatingDescription of the Rating A PASS Clean Pass, no ratings outside theideal ranges. B PASS Pass, one rating outside the ideal range but withinthe secondary allowance, discussed in the description of the test methodabove. F1 1^(st) Degree Fail, the sample failed for having two ratingsoutside the ideal ranges but both within the secondary allowances. F22^(nd) Degree Fail, the sample failed for having one rating outside theboth ideal range and the secondary allowances for that rating. F3 3^(rd)Degree Fail, the sample failed for having one rating outside both theideal range and the secondary allowances for that rating and also havinganother rating outside the ideal ranges but within the secondaryallowances. F4 4^(th) Degree Fail, the sample failed for having tworatings outside the both ideal range and the secondary allowances forthose ratings. F5 5^(th) Degree Fail, the sample failed for having tworatings outside both the ideal range and the secondary allowances forthose ratings and also having a third rating outside the ideal rangesbut within the secondary allowances. F6 5^(th) Degree Fail, the samplefailed for having three ratings outside the both ideal range and thesecondary allowances for those ratings and also having a third ratingoutside the ideal ranges but within the secondary allowances.

Example Set 1

A set of examples is prepared in a Group I (GI) base oil. Each of theexamples contains the same conventional additives package in the sameamount, such that the sample is suitable for use as a lubricant inindustrial gear applications. Each sample is top-treated with one of theSeal Additives described above to see the impact the added materialshave on the formulation's performance, specifically in regards to sealcompatibility.

The conventional additive package used in each of these examples, isreferred to as Additive Package A and contains a metal deactivator, ademulsifier, a rust inhibitor, a mixture of antiwear and extremepressure agents, an antifoam agent, a detergent, and a corrosioninhibitor. None of the additives in Additive Package A meet therequirements for the substituted triazole of the invention.

The samples are tested to evaluate their seal compatibility using thesame test methods described above. The results from the testing ofExample Set 2 are summarized in the table below:

TABLE 1 Summary of Results from Example Set 1 Ex Ex Ex Ex Ex Ex Ex Ex ExEx 1-1 1-2 1-3 1-4 1-5 1-6¹ 1-7 1-8¹ 1-9 1-10 Ex Type Com Inv Inv InvInv Com Inv Com Inv Inv Base Oil GI GI GI GI GI GI GI GI GI GI Add PackA A A A A A A A A A Seal Add A 0 0 0 0 0.2 0.5 0.5 1.0 1.0 0 Seal Add B0 0 0 0 0.2 0.5 0.5 0 0 1.0 Seal Add C 0 0.1 0.3 0.5 0.5 0 0.5 0 0.5 0.5Seal Add D 0 0 0 0 0 0 0 0 0 0 F-S Key F1 B A A A F4 A F2 A A PASS PASSPASS PASS PASS PASS PASS Hardness Δ 6 6 3 3 2 7.5 2 8.5 2 2 % Vol Δ 3 34 5 4 3 5 2.2 5 5 % Tensile Δ −5 −4 −7 −6 −5 3.4 −5 6.1 −5 −5 % Elong Δ−61 −57 −39 −32 −18 −68 −14 −71 −21 −21 ¹Example 1-6 and Example 1-8were each tested twice in two different labs. The results shown forthese samples is the average of the two results obtained for each.

The results show that the inventive examples provide improved sealcompatibility in Group I based formulations over the compositions thatinclude a conventional seal protectant.

Example Set 2

A set of examples is prepared in a Group II (GII) base oil. Each of theexamples contains the same conventional additives package describedabove in Example Set 1. The samples are tested to evaluate their sealcompatibility using the same test methods described above. The resultsfrom the testing of Example Set 2 are summarized in the table below:

TABLE 2 Summary of Results from Example Set 2 Ex Ex Ex Ex Ex Ex Ex 2-12-2 2-3 2-4 2-5¹ 2-6 2-7 Ex Type Com Inv Inv Inv Com Inv Inv Base OilGII GII GII GII GII GII GII Add Pack A A A A A A A Seal Add A 0 0 0 01.0 1.0 0 Seal Add B 0 0 0 0 0 0 1.0 Seal Add C 0 0.1 0.3 0.5 0 0.5 0.5Seal Add D 0 0 0 0 0 0 0 F-S Key F3 B A A F3 B B PASS PASS PASS PASSPASS Hardness Δ 7 6 5 4 7 4 3 % Vol Δ 2 2 4 5 3 6 6 % Tensile Δ −1 −1 −3−8 −7 −8 % Elong Δ −72 −52 −36 −30 −72 −26 −27 ¹A tensile result was notreported for Example 2-5. However, given the results in the otherparameters, it is clear this example failed the test.

The results show that the inventive examples provide improved sealcompatibility in Group II based formulations over the compositions thatinclude a conventional seal protectant.

Example Set 3

A set of examples is prepared in a synthetic base oil chosen for use inwind turbine (WT) applications. Each of the examples contains the sameconventional additives package in the same amount, such that the sampleis suitable for use as a lubricant in industrial gear applications. Eachsample is top-treated with an additional additive to see the impact theadded materials have on the formulation's performance, specifically inregards to seal compatibility.

The conventional additive package used in each of these examples, isreferred to as Additive Package B and contains a mixture of antiwearagents, a mixture of rust inhibitor, a demulsifier, a mixture ofantifoam agents, a corrosion inhibitor, and a copper deactivator. Noneof the additives in Additive Package B meet the requirements for thesubstituted triazole of the invention.

The samples are tested to evaluate their seal compatibility using thesame test methods described above. The results from the testing ofExample Set 3 are summarized in the table below. For this sample set inparticular, one cannot look at the final pass and fail results, butrather must consider the impact on the individual ratings to see theimprovements provided by the present invention. DIN results were alsocollected for this sample set which also show the improvement theinvention provides.

TABLE 3 Summary of Results from Example Set 3 Ex Ex Ex Ex Ex Ex Ex Ex ExEx Ex 3-1¹ 3-2 3-3 3-4 3-5 3-6 3-7¹ 3-8 3-9 3-10 3-11 Ex Type Com InvInv Inv Inv Inv Inv Inv Inv Inv Inv Base Oil WT WT WT WT WT WT WT WT WTWT WT Add Pack B B B B B B B B B B B Seal Add A 0 0 0 0 0.5 0.5 0.5 0.51.0 1.0 1.0 Seal Add B 0 0 0 0 0.5 0.5 0.5 0.5 1.0 1.0 1.0 Seal Add C 00.1 0.25 0.5 0.1 0.25 0.5 1.0 0.1 0.25 0.5 Seal Add D 0 0 0 0 0 0 0 0 00 0 DIN Spec² % Tensile Δ −30.8 −17.7 −18.6 −9.4 −21.2 −9.7 −8.1 −8.3−20.4 −16.9 −6.6 % Elong Δ −47.6 −40.5 −29.9 −19.2 −33.7 −17.5 −10.9−14.3 −32.7 −27.7 −8.4 F-S Key B A A B A B F2 F4 B B F2 PASS PASS PASSPASS PASS PASS PASS PASS Hardness Δ 6.5 5 4 2 4 3 1 −3 3 2 0 % Vol Δ 2.64 5 7 5 6 8.4 8 6 7 9 % Tensile Δ −1.9 −7 −9 −16 −7 −13 −9.2 −25 −9 −14−19 % Elong Δ −58 −55 −50 −39 −55 −48 −22 −19 −54 −45 −35 ¹Example 3-1and Example 3-7 were each tested twice in two different labs. Theresults shown for these samples is the average of the two resultsobtained for each.

The results show that the inventive examples provide improved sealcompatibility in synthetic formulations designed for wind turbines overthe compositions that include a conventional seal protectant, at leastwhen one considers the individual ratings, particularly the change inelongation.

Example Set 4

A set of examples is prepared in a synthetic base oil chosen for use inwind turbine (WT) applications. Each of the examples contains the sameconventional additives package described above in Example Set 3. Thesamples are tested to evaluate their seal compatibility using the sametest methods described above. The results from the testing of ExampleSet 4 are summarized in the table below:

TABLE 4 Summary of Results from Example Set 4 Ex 4-1¹ Ex 4-2² Ex 4-3 ExType Com Inv Inv Base Oil WT WT WT Add Pack B B B Seal Add A 0 0 0 SealAdd B 0 0 0 Seal Add C 0 0.5 0 Seal Add D 0 0 0.5 DIN Spec² % Tensile Δ−31 −9 −4 % Elong Δ −48 −19 −4 F-S Spec Hardness Δ 6.5 2 8 % Vol Δ 2.6 74 % Tensile Δ −1.9 −16 5 % Elong Δ −58 −39 −69 ¹Example 4-1 is identicalto Example 3-1; it is repeated here in this example set for comparisonpurposes. ²Example 4-2 is identical to Example 3-4; it is repeated herein this example set for comparison purposes.

The results show that the inventive examples provide improved sealcompatibility in synthetic formulations designed for wind turbines overthe compositions that include a conventional seal protectant, at leastwhen one considers the individual ratings, particularly the DIN results.

While the invention has been explained, it is to be understood thatvarious modifications thereof will become apparent to those skilled inthe art upon reading the specification. Therefore, it is to beunderstood that the invention disclosed herein is intended to cover suchmodifications as fall within the scope of the appended claims.

In this specification the terms “hydrocarbyl substituent” or“hydrocarbyl group,” as used herein are used in their ordinary sense,which is well-known to those skilled in the art. Specifically, theyrefer to a group primarily composed of carbon and hydrogen atoms that isattached to the remainder of the molecule through a carbon atom and doesnot exclude the presence of other atoms or groups in a proportioninsufficient to detract from the molecule having a predominantlyhydrocarbon character. In general, no more than two, preferably no morethan one, non-hydrocarbon substituent will be present for every tencarbon atoms in the hydrocarbyl group; typically, there will be nonon-hydrocarbon substituents in the hydrocarbyl group. A more detaileddefinition of the terms “hydrocarbyl substituent” or “hydrocarbylgroup,” is described in U.S. Pat. No. 6,583,092.

Each of the documents referred to above is incorporated herein byreference. Except in the Examples, or where otherwise explicitlyindicated, all numerical quantities in this description specifyingamounts of materials, reaction conditions, molecular weights, number ofcarbon atoms, and the like, are to be understood as modified by the word“about.” Unless otherwise indicated, all percent and formulation valueslisted herein are on a weight basis. Unless otherwise indicated, eachchemical or composition referred to herein should be interpreted asbeing a commercial grade material which may contain the isomers,by-products, derivatives, and other such materials which are normallyunderstood to be present in the commercial grade. However, the amount ofeach chemical component is presented exclusive of any solvent ordiluent, which may be customarily present in the commercial material,unless otherwise indicated. It is to be understood that the upper andlower amount, range, and ratio limits set forth herein may beindependently combined. Similarly, the ranges and amounts for eachelement of the invention can be used together with ranges or amounts forany of the other elements. As used herein, the expression “consistingessentially of” permits the inclusion of substances that do notmaterially affect the basic and novel characteristics of the compositionunder consideration.

We claim:
 1. An industrial gear lubricating composition comprising (i)an oil of lubricating viscosity and (ii) a substituted triazole; wherethe substituted triazole includes at least one hydrocarbyl group linkedto one of the nitrogen atoms in the triazole ring.
 2. The composition ofclaim 1 wherein the substituted triazole is present in the lubricatingcomposition from 0.05 to 1.0 percent by weight.
 3. The composition ofclaim 1 wherein the hydrocarbyl group of the substituted triazolecontains from 6 to 40 carbon atoms.
 4. The composition of claim 1wherein the hydrocarbyl group of the substituted triazole includes atleast one nitrogen atom.
 5. The composition of claim 1 wherein thehydrocarbyl group of the substituted triazole includes at least onenitrogen atom and is branched.
 6. The composition of claim 1 wherein thesubstituted triazole comprises a compound having the formula:

or the formula:

or a combination thereof; where, for both formula I and formula II: n isan integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or—(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group containing from 6 to 40carbon atoms, —R²— is a hydrocarbylene group, m is 0 or 1, and each —R³is independently hydrogen or a hydrocarbyl group, so long as the sum ofcarbon atoms in the —R² group and both —R³ groups is from 7 to 40combined.
 7. The composition of claim 6 wherein Y is —R²—NR³R³ and where—R²— is a hydrocarbylene group containing 1 to 2 carbon atoms, and both—R³ groups are branched alkyl groups containing 6 to 20 carbon atoms. 8.The composition of claim 6 wherein the substituted triazole comprises acompound represented by formula (I).
 9. The composition of claim 6wherein the substituted triazole comprises a compound represented byformula (II).
 10. The composition of claim 1 wherein the oil oflubricating viscosity comprises a mineral base oil.
 11. The compositionof claim 1 wherein the oil of lubricating viscosity comprises asynthetic base oil.
 12. The composition of claim 1 further comprising:an antiwear agent, an extreme pressure agent, a friction modifier, acorrosion inhibitor, a rust inhibitor, a metal deactivator, a borateddispersant, a non-borated dispersants, detergent, an antifoam, aviscosity index improver, a viscosity modifier, an additionalantioxidant, a pour point depressant, a seal swell agent, or anycombination thereof.
 13. The composition of claim 1 wherein thesubstituted triazole comprises the reaction product of a triazole, analdehyde and an amine.
 14. A method of lubricating a gear assemblycomprising supplying to said assembly a lubricating compositioncomprising (i) an oil of lubricating viscosity and (ii) a substitutedtriazole; where the triazole includes at least one hydrocarbyl grouplinked to one of the nitrogen atoms in the triazole ring.
 15. The methodof claim 14 wherein the oil of lubricating viscosity comprises a mineralbase oil.
 16. The method of claim 14 wherein the oil of lubricatingviscosity comprises a synthetic base oil.
 17. The method of claim 14wherein the substituted triazole comprises a compound having theformula:

or the formula:

or a combination thereof; where, for both formula I and formula II: n isan integer from 0 to 4; —R is a hydrocarbyl group; —Y is —R¹ or—(R²)_(m)—NR³R³ where —R¹ is a hydrocarbyl group containing from 6 to 40carbon atoms, —R²— is a hydrocarbylene group, m is 0 or 1, and each —R³is independently hydrogen or a hydrocarbyl group, so long as the sum ofcarbon atoms in —R² and —R³ is from 7 to 40 combined.
 18. The method ofclaim 1 wherein the substituted triazole comprises the reaction productof a triazole, an aldehyde and an amine.